Spin Transfer Torque Random Access Memory (STTRAM) is a type of magnetoresistive Random Access Memory (MRAM) which is non-volatile and is typically used for memory circuits, such as, cache, memory, secondary storage, and other memory applications. STTRAM memory may often be operated at reduced power levels and may be less expensive as compared to other memory types.
Spin Transfer Torque (STT) is an effect in which the orientation of a magnetic layer in a magnetic tunnel junction (MTJ) device can be modified using a spin-polarized current. In STT-based MTJs, device resistance can be either low or high, depending on the relative angular difference between the directions of magnetic polarization on both sides of the tunnel junction. Accordingly, one bit state of an MTJ may be represented by a state in which the ferromagnetic layers of the MTJ have a parallel magnetic orientation and exhibit low resistance. Conversely, an opposite bit state may be represented by a state in which the ferromagnetic layers of the MTJ have an anti-parallel magnetic orientation and exhibit high resistance.